CALL911

iTrader: (17)

So my SES light came on about 2 weeks ago in my 98 Formula in my sig. It was driven maybe 5-6 days after that. Then I got in it to drive again on day 7 or so after it came on, and it went back off about 2 minutes after I started driving it I have since driven it at least half a dozen times and the SES light hasn't came on since. I wasn't aware that it would turn itself off. All the other times it came on I had to reset it. I never got it scanned, and it has seemed to run fine both when the SES light was on, and now that its off.

Any ideas? I'm sure I should probably get it scanned just to check it out, but does this normally happen?

firedog02z28

iTrader: (1)

I had the same problem after I installed my headers. Mine was the rear o2s. Get it scanned to make sure. There is a sticky on trouble codes. If it is the rear o2s, just have them tuned out. That is what I did and I have not had a problem yet, in fact it seemed to improve my gas milage by 3 mpg.

Jason

2001NBMZ28

I'd go ahead and get it scanned, most codes stay stored in history for 40 cycles after the MIL shuts off.

CALL911

iTrader: (17)

So is it normal to have the SES light go off on its own? Does this mean that the trouble code has "fixed itself"?

2001NBMZ28

It can shut off after "X" amount of cycles without seeing a failure - depends on the code though. For example if you pull the AIR PUMP fuse it'll throw a secondary air code like P0412, replacing the fuse leaving the MIL illuminated it will turn off after 3 or 4 cold starts and the test runs and sees it's OK again.

zdc590

iTrader: (8)

Mines done that before too, one day i got off the highway, filled it up with some gas and the light was out when i started her back up.

CALL911

iTrader: (17)

Well, at least I know its "normal". I'll try to get it scanned sometime, but honestly its not nearly as big of a concern as it would have been if it would have stayed on.

Thanks fella's.

ghardester

I doubt that you will find a code now that the light is off. If it comes on again get it scanned while the is on.

CALL911

iTrader: (17)

Are you sure? I know for a fact that OBD 1 cars store the trouble codes indefinatly until they are cleared by a scanner even if the check engine light goes off.

I would figure that OBD 2 would be the same at least in that sense.

CJDZ24_Z28

iTrader: (75)

Depends on the code bro. Could of been simple as airpump malfunction. I see you're in NJ. Pep Boys is having a sale on the actron odb II scanner for $49.99. Reads codes and you can clear them yourself. I picked one up finally.

blue98Z

iTrader: (29)

^^Exactly. It depends on the code. I've owned several OBD 1 vehicles and several times the SES light would come on and go off. When I got home to check nothing showed up. I don't have anything to test OBD 2 so I'm not sure how long they may hold a code.

NeedaV8foundation

iTrader: (4)

it might be a cat... how many miles? mine has 63000 and it throws cat codes every now and then, it will turn itself on and off depending on the outside air... best bet is to get it scanned.

ghardester

Yeah, get one. It's a lot cheaper to just read the code yourself and decide if it's a big problem or little one. The '01 Bird of mine would throw a EVAP code if the gas cap wasn't put on right. A simple code reader will cost less than one trip to the shop. The code is just an indication of where to look, not a definitive answer. Here is a sticky that address's what the codes mean.

https://ls1tech.com/forums/general-maintenance-repairs/588124-check-engine-light-codes.html

CALL911

iTrader: (17)

I am strapped for cash right now (and time). I have a buddy that could scan the car for free, its just a matter of making time to check it out.

Like I said before, I am not as concerned as I was before since the light went off. The car will be going under the knife in a few months anyways, and I am doing a ton of work to it. After all of it, it will be tuned, and checked out in full then. Until then, if I get the time to make an appointment with my buddy, then I will. But if its still running fine, and no SES light, then I am fairly confident I'll be okay.

As for the code thing going away, in my 95 Z28 (OBD1), I get a code every time the AC is turned on (as I yanked out the AC years ago in it). And even though hundreds of starts have gone by, and tons of time (talking months, or years in some cases), the code still shows up even if its been that long since I toggled the AC. Perhaps this is one of those codes that "stay" in the system and don't cycle themselves out, but it is proof that at least OBD1 keeps the codes.

CRAGER

Might be that, did you put gas in it within the past few days?

Peace,
Craig.

SVT WUT 7

I concur. Most likely an EVAP code.

Fbody_Freak

I always like when the light starts blinking at me. It's like it's trying to say, "look at me stupid!"